The present invention generally relates to a high voltage generating device and more particularly, to a high voltage generating device such as a fly back transformer or the like for obtaining high voltages to be supplied, for example, to cathode ray tubes, etc. of TV receiving sets, which is provided with a high voltage variable resistor incorporated therein as one unit to obtain high voltages, for example, a focus voltage to be fed to the cathode ray tube, or provided only with a shielding plate for sealing the casing of the high voltage generating device.
In a conventional high voltage generating device, for example, a fly back transformer of the above described type, it has been so arranged that a notch or cut-out portion is formed in a wall of a casing in which high voltage generating components such as a primary winding, a secondary winding, a rectifier, etc. are accommodated, so that a high voltage variable resistor is mounted in said cut-out portion. However, in the known arrangement as described above, since electrically insulating material such as epoxy resin or the like is to be poured or injected into the casing for subsequent hardening thereof, it has been required to employ a sealing member such as a packing and the like, between the cut-out portion in the wall of the casing and the high voltage variable resistor for preventing leakage of the insulating material therethrough during pouring of said insulating material into the casing, thus resulting not only in high cost, but in complication of assembly work of the high voltage generating device itself. Furthermore, even in a case where a high voltage generating device not requiring the high voltage variable resistor is to be constructed with the use of the casing formed with the cut-out portion for mounting a high voltage variable resistor, a shielding plate for closing the cut-out portion is necessary, and in order to tightly seal such cut-out portion, a sealing member such as the packing, etc. must also be employed, thus being still more uneconomical, since in such an arrangement, it is not intended to employ an expensive high voltage variable resistor originally.